"Marine One"

First things first: is everyone okay? I have nail marks in my palms, a rapid heart rate that may never quite return to normal and a deep sense of despair that humanity is doomed. Other than that, I'm just about holding up, and I hope you are too. This was a fantastic finale and it's hard to recall a more tense 90 minutes of television.

What Homeland did wonderfully over the course of this series was rip up the idea of heroes and villains, – and in this last episode the distinction broke down completely. What we were left with was a bleak view of mankind, and a nuanced take on justice. Brody emerges as one of the most heroic characters, in many ways. His suicide tape shows the belief in what is right that informs his "mission". In making his motive something so unequivocally inhumane as a deliberate attack on a school, with the inevitable deaths of children, the writers weren't subtle, but they have allowed us to sympathise with the terrorist as a human being, rather than a faceless threat. And it's a damning indictment of the war on terror, to label politicians "domestic enemies" and "liars and war criminals".

Politicians do not come out of this series well. Vice-president Walden, now running for president, is portrayed as a ruthless careerist who will pursue his aims at any cost; more irritated at having his chief advisor's brains on his shirt than upset about her death. The scenes in the bunker, with Brody's malfunctioning vest, were made slightly less tense by knowing that a second series featuring Lewis and Danes had already been commissioned, but nevertheless it was a remarkable and excruciatingly tense performance. I felt a tiny bit underwhelmed that it was daughter Dana who saved the day, particularly given how much that had been foreshadowed. But any hint of sentimentality was redeemed by the fact that it was Carrie, essentially, who pushed her into doing it; going to Brody's house in one last act of reckless abandon.

Claire Danes' performance in this series has been extraordinary, and she deserves all the awards she has received. To see her so broken at the start of the episode, like a child, asking Saul to "tell me a story", was devastating – she'd been betrayed by Brody, but also by her own mind. With a final neat parallel to Brody's story, she is also in pursuit of a justice, and in many ways, they are fighting against the same enemy. Which brings us to the mole …

There was no big reveal, as I was expecting there to be. The implication appears to be that Estes and the VP had been hindering Carrie's investigations – does that mean that Estes slipped Afsal Hamid the razorblade in the interrogation room? Did he leak the information about the operation to capture Walker? If so, this cover-up is at any human cost, much like the initial drone strike. On reflection, the murkiness of the truth seems fitting considering the tone of the show.

But there is more to come after the aborted suicide mission. Brody meets with Walker – or rather Nick meets with Tom, in one of the rare uses of their first names. Abu Nazir accepts that the vest malfunctioned, or that the benefits of having Brody in office outweigh the idea of assassinating half of the US government. "Why kill a man when you can kill an idea?" he says, somewhat hokily, and not entirely convincingly. That said, when Brody handed Walker the phone and then shot him in the head, the violence of it shocked me. Perhaps it shouldn't have. Brody has already dealt with the guilt of murdering him once. What was left unclear was Brody's motive – was it commitment to the cause, or self-preservation, or both? Is he being co-opted by the system he despises or will he work from the inside for Abu Nazir's change?

Meanwhile Carrie has lost absolutely everything. She submits to electro-convulsive shock therapy, knowing that it may affect her memory, almost willing it to. She understood the case. Saul's final act of care was to let her know that she was right. But it wasn't enough. I respected the writers for only allowing her to be a partial hero, for resisting the temptation to have her run in to the bunker and save the day with triumphant fanfare. This was a bleak, hopeless end to the series, and what a series it's been.

Notes and observations

• Good news: Channel 4 has confirmed it will be bringing UK fans the second series.

•Here's the teaser – which helpfully points out the questions that haven't been answered

• Hatufim, the Israeli series which inspired Homeland, is being screened on Sky Arts 1 from next Thursday, as Prisoners Of War.

• Thank you to all of the commenters who got involved, and particular thanks for the lack of spoilers – given the timelag between UK and US transmission it wasn't easy to avoid them, but I think we just about managed it. I look forward to seeing you all for season two.

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